Partial Discharge Time-Frequency Spectrum Analysis and Extraction for Power Cable

Partial discharge experiment is an important method to evaluate the insulation condition of XLPE power cable system. However, the detection sensitivity of laboratory test or on-site measurement is dependent on background noise and interference. In order to extract the short-time and wide-frequency distribution partial discharge signal from harsh background noise, this paper presents a time- frequency spectrum method based on short-term Fourier Transform (STFT),which calculates the time- frequency spectrum of the original signal, extracts the partial discharge signal who occupy a wide frequency distribution. A outdoor experiment of 110kV power cable exerted with calibration pulse examine the validity of extracting PD waveform from background noise, which lay a foundation for accuracy PD signal extraction and further diagnosis of HV power cable partial discharge on-line detection.